Dear Readers, since the discovery of antibiotics in the first half of the 20th century, their efficacy in managing infectious diseases has been widely evidenced. Their actions on pathogenic bacteria have very often rendered them indispensable and sometimes vital. However, since their antibacterial efficacy is not specific to pathogenic bacteria, their use also leads to a serious imbalance in the gut microbiota, resulting in dysbiosis. Antibiotic-associated diarrhoea, a short-term consequence of post-antibiotic dysbiosis, is well known. Here, Prof. Yvan Vandenplas (Brussels, Belgium) refers to recent work highlighting the medium- and long-term impact of antibiotic intake, especially when administered very early in life.

Faecal transplantation has many potential applications. Prof. Harry Sokol (Paris, France) investigates the results obtained by M. Nieuwdorp and colleagues in patients with metabolic syndrome: faecal transplantation from slim donors improves insulin sensitivity in obese patients with metabolic syndrome. This may also prove to contribute towards advancing our knowledge in pathophysiology. Prof. Emmanuel Mas (Toulouse, France) presents his latest work showing that transferring stools from infants with colic to mice induces visceral hypersensitivity. These results point towards a painful abdominal mechanism and the direct or indirect involvement of the gut microbiota in the pathophysiology of infantile colic.

The gut microbiota was the focus of the 30th congress of the European Helicobacter & Microbiota Study Group (September 7–9, Bordeaux, France) and the Asian Pacific Digestive Week (September 23–26; Hong Kong): Profs. Francis Mégraud (Bordeaux, France) and Uday C. Ghoshal (Lucknow, India) summarise the key points. Finally, in his press review, Prof. Ener C. Dinleyici (Eskisehir, Turkey) comments on the latest recommendations from the World Gastroenterology Organisation on the use of pre- and probiotics in paediatrics and stresses the short- and medium-term consequences of intrapartum antibioprophylaxis in infants. Enjoy your reading.

ANTIBIOTIC TREATMENT IN INFANTS: SHORT AND LONG-TERM CONSEQUENCES OF THE MICROBIOME

The human gut microbiota refers to microorganisms living in the intestine, which have been estimated to equal the total number of human cells in the body. Microbial colonization of the human gut begins in utero as bacteria have been found in the umbilical cord, placenta, amniotic fluid, and meconium [2]. After birth, the gastrointestinal tract is colonized by a rapidly diversifying microbiota, and it is in the early years of life that a stable gut microbiome is established. Microbial colonization is determined by many factors such as the maternal microbiota, delivery mode, feeding, and medication such as antibiotics and proton pump inhibitors. Antibiotics will not only kill bacterial pathogens, but will also profoundly disturb the equilibrium of the gastrointestinal microbiome. The use of antibiotics has increased globally by 36% in the last decade, and they are a well-known cause of dysbiosis. Although the short-term consequences of antibiotic induced-dysbiosis are fairly well known, recent data are emerging concerning the long-term consequences and this is the focus of the present review.

IMPROVEMENT IN INSULIN SENSITIVITY AFTER FAECAL MICROBIOTA TRANSPLANT DEPENDS ON THE INITIAL MICROBIOTA COMPOSITION OF RECIPIENTS

The gut microbiota is involved in insulin resistance although there is limited evidence of a causal link. We compared the effect of faecal microbiota transplant (FMT) from a thin donor (allogeneic) to that of an auto-transplantation (autologous) in male patients with metabolic syndrome. While no metabolic change was observed 18 weeks after FMT, insulin sensitivity was significantly improved at six weeks in the allogeneic FMT group and this was associated with a change in microbiota composition. We also reported changes in plasma concentrations of metabolites, such as γ-aminobutyric acid, and showed that the metabolic response after FMT (defined as the improvement in insulin sensitivity six weeks after FMT) was present in patients with a microbial diversity reduced to basal level. In conclusion, the beneficial effects of FMT from thin donors on carbohydrate metabolism are associated with changes in gut microbiota and plasma metabolites, and can be predicted by the basal microbiota composition of the recipient.

The pathophysiology of infantile colic is poorly understood, though various studies report gut microbiota dysbiosis in colicky infants. Our objective was to test the hypothesis that colic-related dysbiosis is associated with visceral hypersensitivity, triggered by changes in intraluminal content. Faecal samples from seven colicky and seven non-colicky infants were studied. Faecal supernatants (FS) were infused into the colons of C57/Bl6 mice (n=10/specimen). Visceral sensitivity was subsequently assessed in the animals by recording their abdominal muscle response to colorectal distension (CRD) by electromyography (EMG). Serine and cysteine protease activities were assessed in FS using specific substrates. Infant faecal microbiota composition was analysed by 16S rRNA gene pyrosequencing following DNA extraction. FS from colicky infants triggered higher EMG activity than FS from non-colicky infants in response to both the largest CRD volumes and overall, as assessed by the area under the curve of the EMG across all CRD volumes. Infant crying time strongly correlated with mouse EMG activity. Microbiota richness and phylogenetic diversity were increased in the colicky group, without prominent microbial composition alterations. Only Bacteroides vulgatus and Bilophila wadsworthia were increased in the colicky group. The abundance of Bacteroides vulgatus positively correlated with visceral sensitivity. No differences were found regarding protease activities. Luminal contents from colicky infants trigger visceral hypersensitivity, which may explain the excessive crying behaviour of these infants. Additional studies are required to determine the nature of the compounds involved, their mechanism of action, and the potential implications of intestinal microbiota in this age group.

WORLD GASTROENTEROLOGY ORGANISATION 2017

Consistent with previous WGO guidelines, scientific experts evaluated recent publications to prepare their guidelines. These guidelines include information about the definitions, quality, nomenclature, and spectrum of probiotic containing products, as well as the safety and mechanism of action of probiotics and prebiotics.

INTRAPARTUM ANTIBIOTIC PROPHYLAXIS FOR GBS INFECTION

Microbiota composition during early infancy has an important influence on early immunological and metabolic programming that may predispose children to disease risk later in life. The first 1,000 days of life is a critical period for wholelife and early-life events (delivery mode, preterm birth, feeding practices, and antibiotic consumption) which may affect the intestinal and nasopharyngeal microbiota.